Such motor vehicle transmissions are designed inter alia as so-termed dual clutch transmissions, in which the input shafts of the two partial transmissions can each be connected to a drive input by way of a respectively associated powershifting element, wherein the two powershifting elements are combined in a dual clutch. The gears that can be obtained in such a motor vehicle transmission are distributed alternately between the two partial transmissions in such manner that odd-numbered gears are produced by one of the partial transmissions and even-numbered gears by the other. Usually, the individual gears are defined by one or more spur gear stages each with discrete gear ratios, wherein the spur gear stages can be connected into the force flow by associated shifting elements so that a corresponding gear ratio is obtained between the drive input and the drive output of the motor vehicle transmission. Thanks to the alternate distribution of the gears between the two partial transmissions it is possible, while driving in a gear associated with one of the partial transmissions, already to preselect the next gear in the other partial transmission by appropriate actuation of the shifting elements, so that the ultimate change to the next gear is carried out by opening the powershifting element of one partial transmission and shortly afterward closing the powershifting element of the other partial transmission. In this way the gears of the motor vehicle transmission can be shifted under load, which improves the acceleration capability of the motor vehicle by virtue of a gearshift almost free from traction force interruption, and which enables more comfortable gearshift processes. Among others, dual clutch transmission are also designed with the drive input and drive output arranged coaxially with one another and with a countershaft assembly parallel to them both, so that the structure is compact in the radial direction. Furthermore, designs of dual clutch transmissions are known in which the individual gears of the transmission are obtained by directing the force flow via a plurality of spur gear stages, so that compared with conventional transmissions a correspondingly large number of gears can be obtained with relatively few spur gear stages.
From DE 10 2006 054 281 A1 a motor vehicle transmission of this type is known, which is designed as a dual clutch transmission and comprises two partial transmissions having input shafts arranged coaxially with one another. By connecting the respectively associated input shafts by means of a respective powershifting element the two partial transmissions can be connected alternately in a force flow form the drive input to a drive output, in this case the input shaft of the first partial transmission being in the form of a central transmission shaft and the input shaft of the second partial transmission being a hollow shaft. Coaxially with the two input shafts is provided an output shaft which forms the drive output of both partial transmissions, such that rotational movement of the drive input can be transmitted to the drive output with one of a number of discrete gear ratios, the force flow being directed via a countershaft assembly provided parallel to the input shafts and the output shaft. In this case at least two spur gear stages each with a discrete gear ratio are connected into the force flow by actuating associated shifting elements, so that by combining the actuation of the shifting elements and the corresponding guiding of the force flow via the associated spur gear stages, the several gear ratios can be obtained. In addition, however, the rotational movement of the central transmission shaft can be transmitted directly to the output shaft by actuating a shifting element arranged between them.